Marine propulsion device



March 11, 1969 F. T. IRGENS MARINE PROPULSION DEVICE Filed March 20,1967 Sheet AT TOQN EYs March 11, 1969 F. "r. IRGENS MARINE PROPULSIONDEVICE Sheet 3 of 2 Filed March 20, 1967 A Q N 2 w/ 7 3 2 W 0 W p avWIMJ MM ATTORNEY? United States Patent 9 Claims ABSTRACT OF THEDISCLOSURE Disclosed herein is a marine propulsion unit with a waterjacket which surrounds an engine exhaust gas tube and which forms aportion of a recirculating engine cooling system. The lower end of thewater jacket is in fluid communication with the water pump, and theupper end of the water jacket is in communication with the water jacketfor the engine power head. A discharge conduit with a temperatureresponsive valve removes warm water from the power head to maintainuniform operating temperature of the engine. In one embodiment thedischarge conduit dumps into the surrounding Water near the propeller.In another embodiment the discharge conduit dumps into the exhaust gaspassage.

BACKGROUND OF THE INVENTION The present invention is a furtherdevelopment of the subject matter disclosed in US. Patent 3,198,162issued to R. T. Larsen and which discloses a water jacket for an exhaustgas discharge passage in the lower unit of a marine propulsion unit.

SUMMARY OF INVENTION The invention provides a marine propulsion unitwith a water jacket which surrounds the engine exhaust tube and whichforms a portion of the recirculating engine cooling system with thelower end of the water jacket in fluid communication with the water pumpand the upper end of the water jacket in fluid communication with thepower head water jacket. The water jacket for the exhaust tube togetherwith the resilient mounting for the exhaust tube serve to isolate theengine exhaust exitations from the sound radiating surfaces of the lowerunit and accordingly provide vibration and sound isolation between theexhaust gas tube and the lower unit, thus producing a quieter operation.

With the exhaust gas tube water jacket as a part of the engine coolingsystem, in accordance with the invention, water is always contained inthe water jacket when the engine is operating, thus affording quietoperation even when starting or when the engine is idling at a pier orthe like. In addition circulation of the water warmed by the exhaust gastube into the power head water jacket afl'ords quicker engine warm up.

Further objects and advantages of the present invention will becomeapparent from the following description and accompanying drawings.

3,431,882 Patented Mar. 11, 1969 DRAWINGS FIGURE 1 is a partially brokenaway, side elevational view, in fragmentary section, of an outboardmotor embodying various of the features of the invention.

FIGURE 2 is a partially broken away, side elevational view, infragmentary section, of a second embodiment of an outboard motorembodying various of the features of the invention.

DETAILED DESCRIPTION In the drawings, FIGURE 1 shows an outboard motor11 which conventionally includes a transom bracket 13 to which a swivelbracket 15 is connected for vertical swinging movement about ahorizontal pintle 17. The outboard motor 11 includes a power head 18with a water jacket 19 and with an exhaust gas discharge port in theform of an exhaust gas discharge conduit 20. Also included is a lowerunit 21 housing a drive shaft 22 which is connected to a water pump 23which supplies cooling water to the power head water jacket 19.

Included in the lower unit 21 is an exhaust gas duct or passage 31 and alower unit gear case 26 which houses a propeller shaft 27 and drivinggears 28. Shaft 27 drives a propeller 29 having a hollow hub 30.

The exhaust gas passage 31 is formed in part by a generally cylindricalsleeve or tube 35. The tube 35 is resiliently supported by one or moreelastomeric sleeves or mounts 37 and 39 thereby isolating the lower unit21 from any vibration which may be imparted to the tube 35 by theexhaust gas flow. The sleeve or mount 37 is in communication with thelower end of the conduit 20 and has an annular flange 38 which extendsinto and seals the gap between tube 35 and conduit 20. The remainingportion of the exhaust gas passage 31 is formed by an elbow portion 44which extends into the lower unit gear case and which is resilientlyconnected by an elastomeric sleeve or mount 39 to the lower end of thetube 35. The elbow 44 communicates with the interior 46 of the propellerhub 30 for discharge of engine exhaust gas into the surrounding water.

In accordance with the invention there is provided in the lower unit 21means defining a water jacket 47 to damp transmission of vibration orsound exitations to the lower unit caused by engine exhaust gases. Inthe disclosed construction, such means comprises a generally cylindricalsleeve or wall 49 which co-operates with the exhaust gas tube 35 todefine a fluid passage or water jacket 47. The water jacket 47 forms aportion of the recirculating engine cooling system and can be utilizedeither as part of the supply line from the water pump 23 to the powerhead water jacket 19 or as part of the return or recirculating line tothe pump.

In the embodiment illustrated in FIGURE 1, the water jacket 47 forms apart of the recirculating line for re turning water from the power headwater jacket 19 to the pump 23. Water is supplied to the power headwater jacket by the water pump '23 which has vanes 62 secured to driveshaft 22. The vanes 62 rotate in a fixed pump housing 65. Water enterspump 23 through an inlet 66 which communicates with the water pump 23-through an inlet tube 67. Water leaving the pump 23 is carried to thepower head 18 by a tube or pipe 70.

The means connecting the exhaust tube water jacket with the power headwater jacket 47 comprises a port 72 through which water leaves theengine water jacket 19 and enters the exhaust gas tube water jacket 47.

The means connecting the outlet 74 of the water jacket 47 with the pump23 for recirculation comprises a tube 75 connected to the water jacket47 at outlet 74 and connected to the pump 23 at port 79.

Once the power head 23 is at a pre-determined operating temperature, atemperature responsive or thermostatically controlled valve 80 locatedin port 82 will open and permit flow of warm water through a dischargeconduit or tube 84 to maintain generally constant and uniformtemperature in the power head. Discharge tube 84 runs along the side ofsleeve 49 and has a discharge outlet 85 near the propeller 29.

The utilization of the exhaust tube water jacket 47 as a portion of thepower head cooling system, results in maintaining water in the waterjacket 47 whenever the outboard motor 11 is operating, thus affordingquiet operation immediately after starting of the engine and when theassociated boat is docked at a pier or the like and the engine isidling. Furthermore, quicker engine warm up is alforded by exhaust gastube heating of the recirculating water.

In the second embodiment shown in FIGURE 2, the outboard motor 111 has awater jacket 147 formed by co-operation of the exhaust gas dischargetube 135 and wall or sleeve 149. Fluid communication between the powerhead water jacket 171 and the exhaust tube water jacket 147 is affordedby port 172 in the power head water jacket.

Water is supplied to the pump 161 by an obliquely extending scoop 153which is located adjacent to the propeller 129 and which has an inlet154 communicating with a passage 155 communicating with pump 161 througha tube 178.

The pump 161 supplies water to the power head water jacket 171 throughconduit or tube 170 which communicates with the exhaust tube waterjacket 147 at inlet 174. The water entering the exhaust tube waterjacket 147 at inlet 174 fills the exhaust tube water jacket 147 and thenflows into the power head water jacket 171 through port 172. Water isreturned to pump 161 from the power head water jacket 171 by are-circulating line 173.

As in the first embodiment, to maintain uniform engine operatingtemperature the power head 123 is provided with a discharge conduit orpipe 184 which is controlled by a temperature responsive orthermostatically controlled valve 185 and which communicates with thepower head water jacket 171. The conduit 184 extends through apertures187 and 188 respectively in the tube 135 and the sleeve 149 fordischarge of water into exhaust gas discharge passage 131.

Various of the features of the invention are set forth in the followingclaims.

What is claimed is:

-1. In a marine propulsion device including a power head with an exhaustgas port, a lower unit with an exhaust gas tube interiorly of said lowerunit in communication with said exhaust gas port, means in said lowerunit defining a water jacket surrounding said exhaust gas tube, saidwater jacket having an inlet and an outlet, and a recirculating coolingsystem including a pump with an inlet and an outlet, said inletcommunicating with the body of water in which said marine propulsiondevice operates, and a water jacket for said power head, the improvementin combination therewith wherein said exhaust gas tube water jacket is apart of said recirculating cooling system, and means providing fluidcommunication between one of said inlet and said outlet of said exhaustgas tube water jacket with said water pump and the other of said inletand said outlet of said exhaust gas tube water jacket with said powerhead water jacket.

2. A marine propulsion device in accordance with claim 1 wherein saidmeans providing fluid communication between said inlet of said exhaustgas tube water jacket and said pump comprises a conduit connecting saidinlet and said pump outlet.

3. In a marine propulsion device including a power head with an exhaustgas port, a lower unit with an exhaust gas tube in communication withsaid exhaust gas port, means in said lower unit defining a water jacketsurrounding said exhaust gas tube, said water jacket having an inlet andan outlet, and a recirculating cooling system including a pump with aninlet and an outlet, and a water jacket for said power head, theimprovement in combination therewith wherein said exhaust gas tube waterjacket is a part of said recirculating cooling system, and meansproviding fluid communication between one of said inlet and said outletof said exhaust gas tube water jacket with said water pump and the otherof said inlet and said outlet of said exhaust gas tube water jacket withsaid power head water jacket and wherein said means providing fluidcommunication between the other of said inlet and said outlet of saidexhaust gas tube water jacket and said power head water jacket comprisesa port in said power head water jacket in communication with saidexhaust tube water jacket.

4. A marine propulsion device in accordance with claim 1 wherein saidmeans providing fluid communication between the other of said inlet andsaid outlet of said exhaust gas tube water jacket and said power headwater jacket comprises a conduit with one end connected to the powerhead water jacket and the other end connected to the exhaust tube waterjacket.

5. A marine propulsion device in accordance with claim 1 wherein themeans providing fluid communication between one of said inlet and saidoutlet of said exhaust tube water jacket and said water pump comprises aconduit connecting one of said inlet and said outlet of said exhausttube water jacket with said pump.

6. A marine propulsion device in accordance with claim 1 including adischarge conduit in communication with said power head water jacket,said discharge conduit having a temperature responsive valve.

7. A marine propulsion device in accordance with claim 6 wherein saiddischarge conduit communicates with said exhaust gas tube for dischargeof water therethrough.

8. In a marine propulsion device including a power head with an exhaustgas port, a lower unit with an exhaust gas tube in communication withsaid exhaust gas port, means in said lower unit defining a water jacketsurrounding said exhaust gas tube, said water jacket having an inlet andan outlet, and a recirculating cooling system including a pump with aninlet and an outlet, and a water jacket for said power head, theimprovement in combination therewith wherein said exhaust gas tube waterjacket is a part of said recirculating cooling system, and meansproviding fluid communication between one of said inlet and said outletof said exhaust gas tube water jacket with said water pump and the otherof said inlet and said outlet of said exhaust gas tube water jacket withsaid power head water jacket and including a scoop rearwardly of saidpropeller with a fluid inlet, means connecting said scoop inlet withsaid water pump for fluid communication therebetween, and said waterjacket outlet communicates with said means connecting said scoop inletand said water pump.

9. In a marine propulsion device including a power head with an exhaustgas port, a water jacket for said power head, said water jacket havingan inlet and outlet, a lower unit with an exhaust gas tube incommunication with said exhaust port, means in said lower unit defininga water jacket surrounding said exhaust gas tube, said exhaust tubewater jacket having an inlet and an outlet, a drive shaft connected to awater pump, said pump communicating with a water inlet located below thesurface of the water in which the marine propulsion device operates, apropeller shaft, and a propeller, the improvement in combinationtherewith comprising means providing fluid communication between one ofsaid inlet and said outlet of said exhaust gas tube water jacket andsaid water pump, and means providing fluid communication between theother of said inlet and said outlet of said exhaust gas tube waterjacket and said water pump, and means providing fluid communicationbetween the other of said inlet and said outlet of said exhaust gas tubewater jacket and said engine water jacket.

References Cited UNITED STATES PATENTS 3,319,614 5/1967 Shanahan123-4131 X 1,234,293 7/1917 Cowles l-18 3,310,022 3/ 1967 Kollman 173,350,879 11/1967 Boda et a1 115-17 XR FOREIGN PATENTS 831,451 3/ 1960Great Britain.

ANDREW H. FARRELL, Primary Examiner.

US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,431,882 March 11 1969 Finn T. Irgens It is certified that error appears inthe above identified patent and that said Letters Patent are herebycorrected as shown below:

Column 5, line 9, beginning with "said water pump," cancel all to andincluding "water jacket and" in line 12 same column Signed and sealedthis 14th day of April 1970.

(SEAL) Attest:

Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer WILLIAM E. SCHUYLER, JR.

